Make the pastry dough: In a bowl, combine flour and powdered sugar. Rub in the cold butter until the mixture resembles breadcrumbs. Stir in the egg yolk and cold water until the dough just comes together.

Chill the dough: Form the dough into a flat disk, wrap it in plastic wrap, and refrigerate for at least 20–30 minutes.

Roll and line the tart tin: On a floured surface, roll out the dough to fit a 9-inch tart tin. Press it into the tin, trim the edges, and prick the base with a fork.

Blind bake the shell: Preheat the oven to 375°F (190°C). Line the tart with parchment paper and baking weights. Bake for 12 minutes, remove the weights, and bake for another 5–8 minutes until lightly golden. Let cool.

Make the lemon filling: In a mixing bowl, whisk the eggs and sugar until well combined. Add lemon juice, zest, and cream, whisking until smooth.

Pour into the tart shell: Carefully pour the lemon filling into the cooled tart shell.

Bake until set: Reduce oven to 325°F (160°C) and bake the tart for 25–30 minutes, or until the filling is just set with a slight wobble in the center.

Cool and chill: Let the tart cool completely, then refrigerate for at least 1–2 hours to fully set before serving.

Decorate and serve: Dust with powdered sugar or top with berries and cream before slicing.